A number of atherectomy devices have been developed to remove occlusive material, such as plaque and cellular overgrowths, from the interior of a vessel to restore blood flow through the vessel. While many of these previously known devices have been widely accepted for use in interventional procedures, such devices continue to have drawbacks that limit the applicability of the devices in certain circumstances.
U.S. Pat. No. 4,979,951 to Simpson describes a device wherein a distal region carries a housing having an elongated slot. A cutting member disposed within the housing reciprocates pass the slot to sever material protruding into the housing. A drawback of the Simpson device is that it is useful only in arteries large enough to accommodate the housing. In addition, that device cannot be used to remove occlusive material from the walls of tortuous vessels, because the device is incapable of conforming adequately to a curved vessel wall.
U.S. Pat. No. 5,366,464 to Belknap describes an atherectomy device formed from a tapered helical coil covered with a polymeric sheath. A plurality of elongated slots are formed in the helical coil so that the severed ends of adjacent turns of the coil form a flexible cutting edge. While the Belknap device offers the advantages of conforming to tortuous anatomy, and being able to access smaller vessels, it has been determined that the device is prone to failure during use. Specifically, the sheath material in the vicinity of the windows is incapable of sustaining the high torque loads imposed during operation of the device.
U.S. Pat. No. 4,020,847 to Clark describes a rotating cutter device including a slotted cylindrical member disposed at the end of a helical coil. The length of the slotted cylindrical member may make it difficult for the device to pass through or remove occlusive material in tortuous anatomy, or to insert the cutting device into smaller arteries.
In view of the foregoing, it would be desirable to provide an atherectomy device that permits occlusive material to be removed from tortuous and small diameter vessels, and which overcomes the disadvantages of previously known devices.
It further would be desirable to provide an atherectomy device capable of being configured to excise occlusive material from tapered arteries.
It still further would be desirable to provide an atherectomy device that enables occlusive material to be removed from vessels having a tortuous anatomy.